Ultraviolet B UV‑B 280–315
Ultraviolet C UV‑C 100–280
[1] https://en.wikipedia.org/wiki/Ultraviolet
My read is "UVB" is the popular medicine way of saying UV is needed for the body to synthesize vitamin D. It was not considered necessary to point out part of the useful spectrum is in "UVC" territory.
Ultraviolet B UV‑B 280–315
Ultraviolet C UV‑C 100–280
[1] https://en.wikipedia.org/wiki/Ultraviolet
My read is "UVB" is the popular medicine way of saying UV is needed for the body to synthesize vitamin D. It was not considered necessary to point out part of the useful spectrum is in "UVC" territory.